1. Purpose of the gate
This gate decides whether the product's reliability case is strong enough for production. Passing stresses is necessary but not sufficient: the gate also asks whether the measured degradation, projected to the field life the application needs, stays within the ageing allowance the link budget assumed. A laser that passes every stress but loses more power than the budget allowed will fail in the field.
Every failure during qualification is analysed to its root cause. A failure that is understood and fixed may still allow a conditional go; a failure that is not understood normally holds the gate.
What done means at this gate: the parts have passed the stress tests in the plan, laser and coupling degradation is within the allowance the link budget assumed, and every failure has been analysed.
The gate closes the Reliability Qualification stage, which covers showing that the optical parts will last in the field: laser ageing and wear-out, the stability of coupling and adhesives under temperature cycling, damp heat and mechanical shock, photodetector and modulator drift, the electronic die's own qualification to JEDEC practice, and for optoelectronic modules the generic reliability assurance practice the industry publishes, such as Telcordia GR-468.
10 more sections for registered members.